Friday, July 28, 2017

The crop consultant, Mr. Jess McGee, that found sugarcane aphids in a field in Donley County has now found sugarcane aphids in a field in Gray County. Also, Dr. Brent Bean, Director of Agronomy for the United Sorghum Checkoff Program, has been stopping and looking for sugarcane aphids while driving across the Texas High Plains today. He was unable to find any sugarcane aphids in any of the fields, except one forage sorghum field that was west of Canyon in Randall County. He only found one single colony after scouting the field for 30 minutes. Sugarcane aphids numbers are not very high in any of the report fields, but be these findings indicate any grain or forage sorghum field should be closely scouted for the presence of sugarcane aphids. If you discover sugarcane aphids in a field, please contact any of the individuals listed on this site that are contributors for the Texas High Plains.

Tuesday, July 25, 2017

Greg Cronholm, Independent Crop Consultant and retired Extension IPM Agent, just called to report finding sugarcane aphid in Hale County about 3 miles from Plainview. Most were small colonies but some were a bit bigger. Similar to what we saw with the early infestations in Crosby County last week, he said his colonies were in the upper ½ of the plant. For the southern High Plains we now have sugarcane aphid confirmed in Crosby, Lubbock, Hale and Floyd counties.

Sugarcane aphid is just beginning to build in fields in select counties on the Southern High Plains, and as of this writing I know of no fields that have required treatment. The sugarcane aphid distribution map can be found here. So far the aphids are building fairly slowly. This article is posted in the Sugarcane Aphid News site because sugarcane aphids should be considered if headworm control becomes necessary.

The less than good news is that fairly high numbers of headworms (corn earworm + fall armyworm) are being found in panicles. I was in a field in northeastern Crosby county last week that had 1-3 medium to large worms per head, and this field was later treated. Katelyn Kesheimer, IPM Agent in Lubbock and Crosby counties, just reported a field near Shallowater in Lubbock County that had a large number of worms. Stan Carroll, the Research Technician who runs the cotton bollworm/corn earworm traps at the Lubbock Center, told me this morning that he emptied the traps Tuesday night and had a high number of moths in them when he checked them Wednesday morning. We are therefore experiencing a big flight of cotton bollworms/corn earworms. The good news, if you can call it that, is that the fall armyworm trap captures are still well below average.

Insecticide selection for headworms is complicated now that we have sugarcane aphid or the threat of sugarcane aphid in the system. Most of our older insecticides like pyrethroids, Sevin, Lannate etc. will provide control, but they will also eliminate the beneficial insects from the field and leave it more open to damage by the sugarcane aphid. Newer insecticides like Blackhawk and Prevathon will preserve the beneficial insects, but they are more expensive than the older products. Besiege is a combination product; it has the same active ingredient as Prevathon but with a pyrethroid as well. Besiege will not preserve beneficial insects. If a headworm treatment is needed then the risk of sugarcane aphid will have to be factored into the choice of insecticides. As an additional complication, we think our corn earworm is still susceptible to pyrethroids in spite of some slippage downstate, but we know that fall armyworm is less susceptible to pyrethroids, especially the larger worms. One good thing is that headworms do not require the high gallons per acre of spray that sugarcane aphids do, so applications can be made with 3-5 GPA - but check the label for the specific product you intend to use.

Treatment thresholds are based on the size of the worms, number of worms per acre, heads per acre, control cost and value of the crop. For example, in the table below a treatment would be justified at 14,000 large worms (longer than 1/2 inch) per acre when the cost of control was $10/acre and the grain value was $7.00/cwt. To put this in perspective, if the field had 28,000 plants per acre, this would be one large worm per two plants. The online headworm threshold calculator is here.

Friday, July 21, 2017

Dr. Katelyn Kesheimer, IPM Agent in Lubbock and Crosby counties, sent the following notification last night. Given the recent aphid discoveries in nearby Floyd county, and a new discovery this week in Lubbock County, it seems like the annual aphid incursion has begun, albeit at a slower pace than in years past.

"Yesterday I was in a field in northeastern Crosby County that had building populations of sugarcane aphids. It is in the same area that we first found aphids last year as they trickled in from the east and slowly moved west.

SCA colonies were a couple hundred at most and only on a few plants. I’ve attached a picture of one of the colonies – it's mixed with adults, nymphs, and you can see the alates (winged aphids) starting to form. There was also honeydew on some leaves. Yellow sugarcane aphids were in the field as well and populations were starting to build. The field is at soft dough.

We didn’t have a lot of sorghum in our area at the beginning of the season, but with replants the last month there is quite a bit of young sorghum in addition to the acres that are already blooming."

Thursday, July 20, 2017

Yesterday, Brent Bean received a call from Justin McGee, Independent Agronomist, that he had found sugarcane aphids in a field that is located in the very Northwest corner of Donley County. Justin sent me the gps coordinates to the field and I went today, July 20th, and I too found the aphids. I did not doubt Justin’s finding, but I wanted to see for myself before sending out a newsletter with the bad news. From what I found there were very few winged and non winged aphids, one to 4 aphids on a single leaf on a plant, and the percentage of plants infested were less than 10%.

Also, yesterday afternoon Blayne Reed posted to his blog that sugarcane aphids were found in Floyd County by Clay Golden, Independent Crop Consultant, https://halecountyipm.blogspot.com/2017/07/sugarcane-aphid-arrives-in-floyd-county.html. The field was located in Southwestern Floyd County near the community of McCoy. We can hope the sugarcane aphids will be just as slow to build up in the Panhandle as they have been in Lubbock County and in Tom Green County. However, with these findings, scouting for SCAs will, unfortunately, need to be intensified across the Panhandle and the Central Plains.

If you do find sugarcane aphids, please send samples or photos of the aphids to your County Extension Agent, IPM Extension Agent or to Dr. Pat Porter or me, Ed Bynum. This will allow us to better inform everyone where the sugarcane are and the movement of the aphids. We greatly appreciate Justin McGee and Clay Golden for telling us what they found so we can now keep you informed about the movement and activity of the sugarcane aphid.

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